The present invention relates generally to elastomeric hose and a process for manufacturing same and, more particularly, to elastomeric hose having relatively low thermal conductivity.
Low thermally conductive elastomeric hose is generally desirable in applications where a relatively high thermal gradient exists between the temperature of the fluid being carried in the hose and the temperature of the surrounding environment. For example, elastomeric hose having a low thermal conductivity is used to transmit heated water to undersea divers to heat their diving suits. In such applications, the temperature of the heated water may be above about 100.degree. F. while the temperature of the surrounding water may be below 40.degree. F. If hose other than low thermally conductive hose were employed, the heated water would be quickly cooled to an essentially inoperative temperature.
Other applications for low thermally conductive hose include the transmission of a cooled fluid in a heated environment. Examples of such applications include hose used to transmit the coolant in automobile air conditioning systems and hose used to carry cold water in water-cooled machinery. In those instances when hose other than low thermally conductive hose is used, vapor tends to condense on the outside of the hose cover or outer jacket.
Heretofore, in order to provide elastomeric hose having a low thermal conductivity it was necessary to provide hose with a relatively thick outer elastomeric cover. This correspondingly increased the weight and the cost of the hose while decreasing its flexibility. Other methods of providing a low thermally conductive hose include the use of an external cover fitted about and/or adhesively bonded to a hose body which, while concededly, proving to be a good insulator, also increased the weight and cost of the hose while significiantly decreasing its flexibility.
Recently, some low thermally conductive thermoplastic hose has been manufactured having a radially expanded cellular outer cover. An example of such thermoplastic hose is described in U.S. Pat. No. 3,547,162 to Andre Jacques Schaerer. In use however, such hose is less desirable than thermoset hose due to the marked decrease in flexilibity at low temperatures and the low heat distortion points of most thermoplastic materials.
Against the foregoing background, it is a primary objective of the present invention to provide an elastomeric hose having relatively low thermal conductivity.
It is another objective of the present invention to provide an improved reinforced vulcanized hose having a radially expanded, cellular outer cover.
It is an additional object of the present invention to provide an elastomeric hose which remains flexible at low temperatures and which is resistant to heat deformation at elevated temperatures.
It is yet still another object of the present invention to provide a reinforced hose including a radially expanded elastomeric cover having a cellular network formed therein vulcanized to an inner tube.